Gaza's civil defense agency said a pre-dawn Israeli air strike on Friday killed 10 members of the same family, including seven children, in the southern city of Khan Yunis.
The Israeli military said it was looking into the attack, adding in a separate statement that it had struck approximately 40 "terror targets" across Gaza over the past day, AFP reported.
Israel resumed intense strikes on the Gaza Strip on March 18, ending a two-month ceasefire with Hamas.
Efforts to restore the truce have so far failed.
"Ten people, including seven children, were brought to the hospital as martyrs following an Israeli air strike that targeted the Farra family home in central Khan Yunis," agency spokesperson Mahmud Bassal told AFP.
Medics and rescuers transported the dead and injured to hospital in multiple ambulances, with several bodies wrapped in white shrouds and blankets, AFP footage of the aftermath showed.
Footage of the house showed a heavily destroyed structure, with mangled concrete slabs and twisted metal strewn across the site.
Witnesses reported continuous and intensive Israeli tank fire in Khan Yunis.
The civil defense agency also reported two people killed in an Israeli strike in the Al-Atatra area in the northern city of Beit Lahia.
Early on Friday, the Israeli military issued an "urgent and serious" evacuation warning to residents of several areas east of Gaza City.
The Israeli army “is operating with great force in your areas to destroy terrorist infrastructure. For your safety, you must evacuate these areas immediately and move to the known shelters in western Gaza City," Avichay Adraee, the military's Arabic-language spokesman, said on X.
"Overnight, the troops deepened ground activity in the Morag Corridor, while continuing operational activity in the area," a military statement said, referring to a new buffer zone between the southern cities of Rafah and Khan Yunis.
The war in Gaza broke out after Hamas's October 2023 attack that resulted in the deaths of 1,218 people on the Israeli side, mostly civilians, according to an AFP tally based on Israeli official figures.
The health ministry in the Hamas-run territory said on Thursday that at least 1,522 Palestinians have been killed in the renewed Israeli operations since March 18, taking the overall death toll since the start of the war to 50,886.